Temperature resistant polymer networks are critical for an increasing number of industrial market applications. Applications are diverse from building and construction, electronics packaging, energy and power generation, and transportation. As the environmental temperature of an application increases, the number of available materials able to meet requirements shrinks rapidly.
Phthalonitrile (PN) resins are a class of network forming resins that when polymerized supply excellent thermal stability and degradation resistance, yet commercialization of phthalonitrile resin technology and use is hindered by poor processing properties, high cost, and high temperature autoclave cures. Phthalonitrile resins have high melt temperatures due to the rigid structure of many phthalonitrile molecules which incorporate a large percentage of aromatic structures to maintain the thermal performance of the phthalonitrile polymerized network. The phthalonitrile moiety is also rigid and planar and has a tendency to crystallize. These molecular structure attributes contribute to the high melt temperature of multifunctional PN resins. The high cost of the resin is driven by resin synthesis which utilizes higher cost starting materials (similar to anhydride and imide resins) and multistep synthesis routes. A high glass transition temperature of the polymerized resin imparts excellent thermal stability at high service temperatures, but also contributes to the need for high temperature multistep autoclave cures under inert atmosphere to achieve near full conversion.